7.1 Overview

This 16-bit edge-triggered D-type flip-flop is designed for 1.65-V to 3.6-V V_CC operation.

A buffered output-enable (OE) input can be used to place the eight outputs in either a normal logic state (high or low logic levels) or the high-impedance state. In the high-impedance state, the outputs neither load nor drive the bus lines significantly. The high-impedance state and increased drive provide the capability to drive bus lines without interface or pull-up components.

OE does not affect internal operations of the flip-flop. Old data can be retained or new data can be entered while the outputs are in the high-impedance state.

To ensure the high-impedance state during power up or power down, OE should be tied to V_CC through a pull-up resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.

Inputs can be driven from either 3.3-V or 5-V devices. This feature allows the use of this device as a translator in a mixed 3.3-V/5-V system environment.

Active bus-hold circuitry holds unused or not driven inputs at a valid logic state. Use of pull-up or pull-down resistors with the bus-hold circuitry is not recommended.

The SN74LVCH16374A is particularly suitable for implementing buffer registers, I/O ports, bidirectional bus drivers, and working registers. It can be used as two 8-bit flip-flops or one 16-bit flip-flop. On the positive transition of the clock (CLK) input, the Q outputs of the flip-flop take on the logic levels set up at the data (D) inputs.

This device is fully specified for partial-power-down applications using I_off. The I_off circuitry disables the outputs, preventing damaging current backflow through the device when it is powered down.

7.2 Functional Block Diagram

Figure 4. Logic Diagram (Positive Logic)

7.3 Feature Description

• Wide operating voltage range
  • Operates from 1.65 V to 3.6 V
• Allows down voltage translation
  • Inputs accept voltages to 5.5 V
• I_off feature
  • Allows voltages on the inputs and outputs when V_CC is 0 V
• Bus Hold on data inputs eliminates the need for external pull-up or pull-down resistors

7.4 Device Functional Modes